CVE-2020-13757

Name: CVE-2020-13757
Creator: NVD / NIST
Published: 2020-06-01T19:15:10.067+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.36%

Last modified Jun 17, 2026

CVE-2020-13757 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Python-RSA before 4.1 ignores leading '\0' bytes during decryption of ciphertext. This could conceivably have a security-relevant impact, e.g., by helping an attacker to infer that an application uses Python-RSA, or if the length of accepted ciphertext affects application behavior (such as by causing excessive memory allocation).. EPSS estimates a 1.36% chance of exploitation in the next 30 days.

Description

Python-RSA before 4.1 ignores leading '\0' bytes during decryption of ciphertext. This could conceivably have a security-relevant impact, e.g., by helping an attacker to infer that an application uses Python-RSA, or if the length of accepted ciphertext affects application behavior (such as by causing excessive memory allocation).

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

1.36%

68.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-327

Affected Software

Vendor	Product	Versions
Python-Rsa Project	Python-Rsa	< 4.1
Fedoraproject	Fedora	31
Fedoraproject	Fedora	32
Canonical	Ubuntu Linux	14.04

References

https://github.com/sybrenstuvel/python-rsa/issues/146Issue Tracking, Third Party Advisory
https://github.com/sybrenstuvel/python-rsa/issues/146#issuecomment-641845667Exploit, Issue Tracking, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2KILTHBHNSDUCYV22ODLOKTICJJ7JQIQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZYB65VNILRBTXL6EITQTH2PZPK7I23MW/
https://usn.ubuntu.com/4478-1/Third Party Advisory
https://github.com/sybrenstuvel/python-rsa/issues/146Issue Tracking, Third Party Advisory
https://github.com/sybrenstuvel/python-rsa/issues/146#issuecomment-641845667Exploit, Issue Tracking, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2KILTHBHNSDUCYV22ODLOKTICJJ7JQIQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZYB65VNILRBTXL6EITQTH2PZPK7I23MW/
https://usn.ubuntu.com/4478-1/Third Party Advisory

Timeline

Published: Jun 1, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-13757?

How severe is CVE-2020-13757?

CVE-2020-13757 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.36% probability of exploitation in the next 30 days.

How do I fix CVE-2020-13757?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-13757?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST